Is the TI spice model for the LMP8645 wrong? Using TI spice, I get an unexpectedly large offset error; I didnt expect this for a part with specs of Vos = 1mV and Ib = 23uA.
Using high side current sensing through a .005 ohm sense resistor as shown below, the result is about 60mV on the output when the load current is very low. For example sweeping R2 (in my cct below) from 50 ohms down to to 1 ohm (corresponding to load current of 240mA to 12A) the output sits at about 60mV until the load reaches / exceeds about 1.5A then starts to rise (reaches 82mV @ 12A).